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cliffski writes "According to the BBC website the UK govt has just given the go ahead to two large offshore wind-farm projects.
Between them the schemes would produce enough renewable electricity to power about one million households.
The larger London Array project covers 144 sq miles (232 sq km) between Margate in Kent and Clacton, Essex and will be the world's biggest when it is completed. The £1.5bn scheme will have 341 turbines rising from the sea about 12 miles (20km) off the Kent and Essex coasts, as well as five offshore substations and four meteorological masts"

Why don't they put these wind farms on barges floating around the seas offshore, where the winds blow steady and reliable? Relocated when economical according to satellites tracking the seasonal winds.

Barges covered with solar cells. And reverse-gyroscopes that generate power from waves and currents. They anchor landmines, don't they?

Compare the number of bird deaths from those windfarms to the number of bird deaths (and non-bird deaths) that would result if it was a coal burning power plant instead. Every project has costs (not all costs are $$). Hopefully the people in charge weigh the environmental costs as well as the monetary costs (sometimes the environmental costs end up being monetary costs anyway). Most large scale power generation techniques have an environmental impact.. The question is - do the benefits outweigh the costs?

I've never understood why the power of tides is not exploited more. In a short streach of coast around the UK, hundreds of millions of tons of water must be moved every 24 hours. I'm sure there must be a lot more energy in that than in the wind in the same area. Why isn't that exploited? Anyone know?

Most of the water that is being moved by tides isn't moving very fast, or very far. Tidal power is most efficient where the world's largest tides can be found, such as the Bay of Fundy in Canada.

There is tidal power being generated in the Bay of Fundy, there has been a 20MW generator operating for the last 20 years. However, it is expensive (operating in salt water isn't the most friendly enviromnent), and expanding it would put a large strain on the ecosystem.

This isn't a lot of power though. 20 large windmills could produce the same or more power, for much less cost. Incidentally, Nova Scotia, which borders half of the Bay of Fundy, has some of the world's strongest and most consistent winds.

Don't worry - the windmills aren't actually that efficient, nor do they cover a large percentage of vertical cross-section. They're spaced quite a bit apart and aren't that tall, vertically speaking. Chances are they don't end up being more disruptive to air currents than, say, the skyscrapers in NYC. And the weather in Brooklyn isn't *that* different than in the rest of the region.

The problem with wind energy is that it's output is unreliable and unlikely to match demand. For electricity, it is essential that supply match demand very strictly. Essentially, this means that wind farms have to be backed up with other, reliable, fast-switching power sources. This, of course, means you've still not solved the energy problem - what do these other plants run on? Also, it adds to the cost of electricity from wind - which is already very high.

You might think that making all the concrete, metal, plastics, etc, involved in the manufacture of all the generators will put a large burden on the environment, but actually compared to the energy investment in building, running, and decommissioning a nuclear power plant, the environmental burden is quite light:
http://www.eoearth.org/article/Energy_return_on_in vestment_(EROI)_for_wind_energy [eoearth.org]

Well, where I live, A/C is pretty much a given. With Summer temperatures running in the mid 90s to the mid 100s (35-39c), there is no amount of insulation short of ~20 feet of earth thrown over your house that will make a difference. You're going to need something, and while insulation means that it'll be cooler until ~13:00, after that it just means it'll stay warm longer.

Still, the first thing I did when I bought my new house was to put another layer of insulation in the attic, and get a quote for having more insulation put into the outside walls as well.

It only makes sense to add extra insulation...In the north you get a lot of people talking about the insulation, because in their minds insulation keeps you warm, and they think about that. It's not so much the case in the south, because people think of insulation as keeping you warm and thats the LAST thing they want. It's more a problem of education than anything else.

Where I live we have the same temperature range in summer (which is now, actually), humidity of 80% or so is normal. What *really* matters is that it becomes cool during the night, if it doesn't, AC is the only thing that will save you, since at my house we respect the laws of thermodynamics;)
At night, we open doors and windows and let the cool air in, at around 10-11am we close everything (including most blinds), and it remains cool for the whole day. Our walls are about 20cm of brick (normal width) and we have single pane windows (well, my cousin lives 30 minutes from town and he has double pane).
We do have an AC, but it doesn't cool the whole house (it's a large house). Old houses (my mother's accounting studio is actually an old house) have very high ceilings (6 metres or so), which also help.

I used to do that when I lived in New York...That was completely effective, you could close all the windows at 7:00am, and the house would stay decently cool until around 2:00 or 3:00, and then you'd open all the windows and sweat until 5:30 or 6, when it would start cooling off.

In Georgia, however, the nights are almost as miserable as the days because the humidity in the air traps the heat...it's literally like a sauna...and leaving your AC off for hours means it has to work harder to cool things back off when you finally cave in and turn it on. It's probably still a net savings, but in July I don't even consider it.

I'm always interested in better insulation...The house has too many damn windows though, and I'm not planning on living there long enough to make my money back on replacing them, which is an issue. I've still done a few, but it's ~200.00 per window, not counting installation, so I'm not in any hurry.

Well, there's also the matter of latitude to remember here, when comparing Europe and the USA. I live in Phoenix, which is at approximately the same latitude as Baghdad. Most of the USA lines up with the Mediterranean, not with Scandinavia.

At high altitudes in AZ, you can get away with passive cooling if you have excellent insulation. You can open the doors and windows at night, and close them during the day, and keep your house livable. At low altitudes like Phoenix, however (~1500'), that's a fool's errand. Summer nights may not dip below 90 F for weeks, and can sometimes be 100 F. You would have to live in an underground bunker to get any kind of passive cooling. The only solution to "being too hot" is AC.

Of course, it's nice during the winter, because we can do passive heating;) Can you guys do that? Stop wasting energy on heat, ya savages!

The secret in Georgia is to not cut down all your trees. My last house had several tall old growth trees that created a canopy over the house.

No sun hitting the roof means little heat getting into the house.

This was in a house from the 40's with absolutely NO insulation ANYWHERE in the house. I ran the A.C. in late July - September and only after 3pm or so to bring it back down a bit and it would hover in the lower 70's all day. Now, heating the bitch in the winter cost me nearly $200 a month (natural gas), but my power bill would raise maybe $10-$15 during the summer tops. I suspect that with proper insulation and windows a house under trees wouldn't need the A.C. much if at all.

I'm in Michigan, and I don't think I can even get single pane exterior windows unless it's by special order, and I'd never pass inspection with them. Even old construction has blown in insulation in the wall or foam, unless it a tenement in Detroit. Still I don't think primative areas like California, New York and Florida define average for the United States.